Question marks remain over why Napier is losing a fully functioning police station.

Work will start next month on Napier's new police station.

The 50-year-old building on Station Street is being replaced with a 'satellite' station, costing more than $5 million.

The police district headquarters in Napier will also be vacated and staff moved to a new hub building in Hastings.

The change will result in about 100 fewer police staff based out of Napier.

Napier MP and Labour's Police spokesperson Stuart Nash said the move's going to put public confidence in police at risk.

"We've lost our hospital, we got a satellite heath centre. We're losing our police station and having a satellite station. I would've thought 60,00 people is a city large enough to justify its own fully functional station".

Excavation work at the site will start in early April and is expected to be finished by December.

The station in Hastings is also being demolished and will be replaced with an $18 million police district 'hub' building.